Intelligent tape drive assembly that diagnoses and repairs its own tape drives

ABSTRACT

A tape drive assembly ( 20 ) for the transmission of data relative to a magnetic storage tape ( 278 ) includes a tape head ( 260 ), a cartridge receiver ( 268 ) and a controller ( 44 ). The cartridge receiver ( 268 ) selectively receives a cartridge ( 54 ) having a lapping tape ( 478 ) that laps the tape head ( 260 ). The controller ( 44 ) dynamically adjusts one of (i) a tension of the lapping tape ( 478 ) relative to the tape head ( 260 ), (ii) an oscillation frequency of the tape head ( 260 ) relative to the lapping tape ( 478 ), and (iii) a lateral velocity of the lapping tape ( 478 ) relative to the tape head ( 260 ). The controller ( 44 ) can use an algorithm to adjust these conditions. The algorithm can be based on the pliability of the lapping tape ( 478 ), a curvature of the tape head ( 260 ) and/or the grit of the lapping tape ( 478 ). In addition, or in the alternative, the algorithm can be based on at least one of an output of the tape head ( 260 ), a resolution of a signal from the tape head ( 260 ), an error rate in reading of data by the tape head ( 260 ) from the storage tape ( 278 ), an error rate in writing of data by the tape head ( 260 ) to the storage tape ( 278 ), and a signal-to-noise ratio from the tape head ( 260 ).

BACKGROUND

Tape cartridges can store a vast amount of data. Tape drives, usedeither singly or in a tape library (also referred to as a medialibrary), each include a data transducer or head (such as amagnetoresistive (MR) head) that reads and/or writes data to the tapecartridges. For proper operation of the tape drive, the head mustmaintain very close proximity to the storage tape of the tape cartridgein order to provide the ability to record and reproduce signals. Thehead operates in an open environment and can be exposed to variouscontaminants from the open air and/or from the storage tape itself.Today's heads require very low separation between the head and thestorage tape for greater accuracy in reading and writing of data.Excessive separation between the head and the storage tape and/or sensordamage such as scratches, nicks or other abrasions to the head itselfcan result in reading and writing errors or even head failure.

It is well known that tape to head separation increases whencontaminants build up on the surface of the head. Cleaning cartridges orbrushes can be used to remove contaminants. Unfortunately, these typesof cleaning devices can be relatively ineffective for removing hardeneddeposits on the head. Further, when the sensor of the head is impactedwith sufficient force, or when a conductive material causes a short inan element in the head, the head is rendered unusable and the drive mustbe repaired. In addition, contaminants and tape abrasive materials cangenerate surface scratches that effectively create permanent separationbetween the tape and the sensor that also reduces the head signal,requiring repair to the head.

Presently, the drive repair process can be lengthy, complex and costly.For example, when a tape drive fails within a media library, the drivemust be shipped back to the factory where it undergoes a screeningprocess that attempts to identify the drive or drives having failedheads. Drives with suspect heads are disassembled and heads arecarefully removed. Failed heads are returned to head vendors for repair.The head repair procedure can be proprietary to each head vendor,further complicating the entire process. Typically, the head repairincludes lapping of the head, followed by testing. This “lap and test”procedure is repeated until a satisfactory result is achieved, or untilthe head is deemed irreparable. The head is then sent back to beinstalled into a rebuilt drive, and after a complete retest, the rebuiltdrive is returned so that it can be reinstalled for the customer.

SUMMARY

The present invention is directed toward a tape drive assembly for thetransmission of data relative to a magnetic storage tape. In oneembodiment, the tape drive assembly includes a tape head, a cartridgereceiver and a controller. The tape head magnetically interacts with thestorage tape. The cartridge receiver selectively receives a cartridgehaving a lapping tape that laps the tape head. In this embodiment, thecontroller dynamically and/or intelligently based on the result of eachtest adjusts the lapping conditions including one or more of (i) atension of the lapping tape relative to the tape head, (ii) anoscillation frequency of the head relative to the lapping tape, and(iii) a lateral velocity of the lapping tape relative to the tape head.In certain embodiments, the cartridge includes both the storage tape andthe lapping tape.

In some embodiments, the controller uses an algorithm to adjust thetension of the lapping tape relative to the tape head, to adjust theoscillation frequency of the tape head relative to the lapping tape,and/or to adjust the lateral velocity of the lapping tape relative tothe tape head. The algorithm can be based on the pliability of thelapping tape, a curvature of the tape head and/or the grit of thelapping tape. In addition, or in the alternative, the algorithm can bebased on at least one of an output of the tape head, a resolution of asignal from the tape head, an error rate in reading of data by the tapehead from the storage tape, an error rate in writing of data by the tapehead to the storage tape, and a signal-to-noise ratio from the tapehead.

An embodiment of the present invention is also directed toward one ormore methods for repairing a tape drive by adjusting various parametersand/or modifying and/or updating the drive or controller micro code.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with further advantages thereof, may best beunderstood by reference to the following description taken inconjunction with the accompanying drawings, taken in conjunction withthe accompanying description, in which similar reference charactersrefer to similar parts, and in which:

FIG. 1 is a block diagram of one embodiment of a media library havingfeatures of the present invention including a plurality of tape drivesand a plurality of tape cartridges;

FIG. 2 is a top view of a portion of one embodiment of the tape driveand the tape cartridge;

FIG. 3 is a side view of a portion of one embodiment of the tape driveincluding a tape head and a controller, and a portion of the tapecartridge including the tape;

FIG. 4 is a side view of a portion of one embodiment of a tape of thetape cartridge;

FIG. 5 is a side view of a portion of another embodiment of the tape ofthe tape cartridge;

FIG. 6 is a side view of a portion of yet another embodiment of the tapeof the tape cartridge;

FIG. 7 is a flow diagram illustrating one embodiment of a method forrepairing the tape drive in accordance with the present invention; and

FIG. 8 is a flow diagram illustrating another embodiment of a method forrepairing the tape drive in accordance with the present invention.

DESCRIPTION

FIG. 1 is a simplified schematic view of one embodiment of a medialibrary 10, in the form of a multi-drive, mass storage and retrievaltape library/loader unit. In one embodiment, the media library 10includes a housing 12, a power supply 14, a plurality of drive assemblyreceivers 18, a plurality of tape drive assemblies 20-1, 20-2, 20-3(also sometimes generically referred to herein as tape drive assemblies20), one or more cartridge retainer receivers 22, a cartridge mover 24including a cartridge pass-through and/or rotating elevator 26, at leastone cartridge elevator guide shaft 28, a drive shaft 30, a rack driveshaft 32, a cartridge elevator motor 34, a pulley drive assembly 36, aroller drive shaft motor 38 and a rack drive shaft motor 40. The housing12 may be constructed of any number and/or type of conventionalmaterials such as, for example, those utilized in industry standard rackmount cabinets. It is recognized that many different suitable types ofcartridge movers 24 can be utilized in the media library 10, and thatthe cartridge mover 24 provided herein is merely representative of onesuch type and is not intended to limit the scope of the presentinvention in any manner.

In this embodiment, the power supply 14 can provide electrical power tothe plurality of drive assembly receivers 18, one or more of the tapedrive assemblies 20, the cartridge elevator motor 34, the roller driveshaft motor 38, and/or the rack drive shaft motor 40. The power supply14 is interfaced with these components as well as with an external powersource using industry standard cabling and connections (not shown).

Each of the drive assembly receivers 18 receives one of the tape driveassemblies 20. As provided herein, each of the tape drive assemblies 20can include a corresponding tape drive 46-1, 46-2, 46-3 (i.e. QuantumDLT 2000XT™, DLT4000™, DLT7000™, DLT8000™, DLT VS80™, DLT VS160™, DLTV4™, DLT S4™, SDLT 320™, SDLT 600™, LTO-2™, LTO-2 HH™, LTO-3™, LTO-3HH™, DAT 72™, DDS-4™, or equivalent, as non-exclusive examples).

The tape drive assemblies 20-1, 20-2, 20-3 within the media library 10can be substantially identical to one another. Alternatively, one ormore of the tape drive assemblies 20-1, 20-2, 20-3 within the medialibrary 10 can be different from the remaining tape drive assemblies20-1, 20-2, 20-3 in the media library 10. The tape drive assemblies 20include one or more controllers 44 (one controller 44 is illustrated inFIG. 1). In one embodiment, each tape drive assembly 20-1, 20-2, 20-3includes a separate controller 44. Alternatively, the tape driveassemblies 20-1, 20-2, 20-3 can share a single controller 44.

Each tape drive 46-1, 46-2, 46-3 (generically referred to as tape drive46) includes a cartridge receiver 48-1, 48-2, 48-3 (generically referredto as receiver 48) and a corresponding cartridge sensor 50-1, 50-2, 50-3(generically referred to as sensor 50) within the cartridge receiver 48.The cartridge receiver 48 receives one of a plurality of cartridges 54D,54L, 54C (generically referred to as cartridge 54), which are adaptedfor use in the media library 10. The cartridge sensor 50 can generate acartridge presence signal when the cartridge 54 is present within thecartridge receiver 48 of the tape drive 46. This signal from one tapedrive 46 can be provided to the controller 44 and/or to another tapedrive 46 in the same media library 10 or in a different media library10.

Each of the cartridge retainer receivers 22 can receive a standardcartridge retainer 51, such as a tape magazine in one non-exclusiveexample, which includes a plurality of cartridge receivers 52. Thecartridge retainer 51 includes a cartridge presence indicator 56 withineach cartridge receiver 52 which indicates the presence and/or absenceof a cartridge 54 within the cartridge receiver 52.

In the embodiment illustrated in FIG. 1, the cartridge mover 24 ispositioned within the housing 12 between the plurality of cartridgereceivers 52 and the plurality of cartridge retainer receivers 22. Inthis manner, the cartridge mover 24 is able to load and unload one ofthe cartridges 54 to and from all of the tape drives 46 and cartridgeretainers 51 within a given media library 10. Further, the input of oneor more cartridges 54 into the cartridge receiver 52 of one or more tapedrives 46 can be automated, or it can be manually undertaken by anoperator, for example.

In the embodiment illustrated in FIG. 1, the controller 44 is physicallypositioned remotely from the tape drives 46. In an alternativeembodiment, the controller 44 is incorporated into one or more of thetape drives 46. For example, the controller 44 can physically residewithin or on one or more of the tape drives 46.

In one embodiment, the controller 44 can include a standard driverinterface unit for receiving digital commands and translating thecommands into driving currents, such as step pulses for controllingstepper motors. Further, the controller 44 can include a standardprogrammable general purpose computer formed on a single plug-in cardunit and preferably includes a programmed microprocessor ormicrocontroller according to the present invention, memory,communication interface, control interface, connectors, etc. Thecontroller 44 can form part or all of the drive circuitry, which caninclude or comprise a printed circuit board assembly (not shown), in onenon-exclusive example.

The media library 10 can use well-known industry standard cabling andcommunication protocols between the controller 44 and other componentsof the media library 10. Cabling and electrical characteristicsincluding signaling protocols can be generally standardized, and thelogical message protocols can be either proprietary or standardized asknown to those skilled in the art.

Additionally, as set forth in greater detail below, the controller 44can determine whether a problem with one or more tape drives 46 may beoccurring. For example, the controller 44 can monitor the reading and/orwriting error rate of the tape drive 46 to determine if this error rateis above a predetermined threshold. If so, the controller 44 can takecertain steps to mitigate or reduce the error rate, as described below.Alternatively, the controller 44 can monitor other performanceparameters to determine whether a performance problem may exist with oneor more of the tape drives 46.

Various non-exclusive examples of performance parameters include thecontroller 44 monitoring an output of the tape drive 46, a resolution ofa signal from the tape drive 46, an error rate in reading of data fromthe cartridge 54, an error rate in writing of data to the cartridge 54,and/or a signal-to-noise ratio (S/N ratio) of the tape drive 46. Thecontroller 44 can determine whether these or other suitable parametersare above or below a predetermined threshold level for each parameter,at which point the controller 44 can selectively initiate correctiveaction in accordance one or more embodiments described herein. Incertain embodiments, the controller can use an algorithm that is basedon one or more of the above performance parameters to determine whethercorrective action is required for the tape drive, as more fullydescribed below. In an alternative embodiment, the tape drive's owndrive circuitry can provide one or more of the above-referencedfunctions provided by the controller 44.

The types of cartridges 54 in the media library 10 can vary. Forexample, the cartridges 54 can include one or more data cartridges 54D,one or more lapping cartridges 54L and/or one or more combinationcartridges 54C. The data cartridge 54D includes a magnetic storage tapethat is adapted to store data. The lapping cartridge 54L includeslapping tape that is adapted to perform a lapping operation on a portionof the tape drive 46. The combination cartridge 54C includes both thestorage tape and the lapping tape, as described in greater detail below.

Any number of each type of cartridge 54 can be present within the medialibrary 10 to satisfy the design requirements of the media library 10.In certain embodiments, all three types of cartridges 54D, 54L, 54C arepresent. Alternatively, one or more of these types of cartridges 54D,54L, 54C may be absent from the media library 10. Still alternatively,the media library can also include other types of cartridges, such as acleaning cartridge 54CL that includes a cleaning tape for cleaning dustor other particulates from portions of the tape drive 46. In anotherembodiment, the cleaning tape can also be included as part of thecombination cartridge 54C.

In one embodiment, two of more different types of cartridges 54D, 54L,54C generally have a substantially similar form factor. In anotherembodiment, the form factor for two or more of the cartridges 54D, 54L,54C can be different.

FIG. 2 illustrates one embodiment of a cartridge 254 and the tape driveassembly 220, which includes one tape drive 246. It is recognized thatthe tape drive assembly 220 described herein can be part of the medialibrary 10 as illustrated in FIG. 1, or the tape drive assembly 220 canbe a stand-alone type of assembly.

In the embodiment illustrated in FIG. 2, the tape drive 246 includes adrive housing 258, a tape head 260, a take-up reel 262 having a driveleader 264 and a take-up reel hub 266, a cartridge receiver 268, abuckler 270 and the controller 244. In one embodiment, the cartridge 254includes a cartridge housing 272, a cartridge reel 274 having acartridge hub 276 (shown in phantom), a tape 278, and a cartridge leader280 having a cartridge buckle component 282. The buckler 270 secures thedrive leader 264 to the cartridge leader 280. The buckler 270 moves thedrive leader 264 relative to the cartridge leader 280 to automaticallybuckle and/or unbuckle the drive leader 264 to the cartridge leader 280in ways known to those skilled in the art. Further, the specific type ofbuckler 270 included in the tape drive assembly 220 can include any typeof device that secures the drive leader 264 to the cartridge leader 280,and can be varied in ways known to those skilled in the art.

The drive housing 258 retains the various components of the tape drive246, including at least the tape head 260 and the cartridge receiver268. In the embodiment illustrated in FIG. 2, the tape drive 246 furtherincludes a plurality of tape rollers 283 and tape guides 284 which arecoupled or directly secured to the drive housing 258. The tape rollers283 and tape guides 284 guide the tape 278 along a tape path across thetape head 260 and onto the take-up reel 262. In one embodiment, the tapedrive 246 includes three tape rollers 283 and two tape guides 284.However, any suitable number of tape rollers 283 and/or tape guides 284can be included in the tape drive 246.

The tape 278 is secured to the cartridge hub 276 on one end and thecartridge leader 280 on the other end. As illustrated in FIG. 2, thecartridge 254 includes a single cartridge reel 274. In an alternateembodiment (not shown), the cartridge 254 can include two or morecartridge reels 274.

In this embodiment, the tape drive 246 also includes a take-up reelmotor (not shown) that rotates the take-up reel 262, and a cartridgereel motor (not shown) that rotates the cartridge reel 274. Therotational force of the take-up reel motor relative to the cartridgereel motor determines the tension of the tape 278 moving across the tapehead 260. In certain embodiments, the controller 244 dynamicallycontrols the rotational force of the take-up reel motor and thecartridge reel motor to dynamically control the tension of the tape 278relative to the tape head 260. In alternative embodiments, the tensionof the tape 278 can also or alternatively be controlled by thecontroller 244 in other suitable ways, such as by controlled movement ofthe tape head 260 toward and/or away from the tape 278, or vice versa.

In one embodiment, the tape 278 of one of the cartridges 254 includes astorage tape only, which magnetically stores data in digital form. Inanother embodiment, the tape 278 of one of the cartridges 254 includes alapping tape only, which includes a relatively abrasive material such as0.5 micron diamond tape that can inhibit severe induced shorts, andreduce or remove scratches and other imperfections, persistent depositsand other particulates or contaminants from the tape head 260. In stillanother embodiment, the tape 278 in one of the cartridges 254 caninclude a combination of at least two different types of tape, such asthe storage tape and the lapping tape, as one non-exclusive example. Itis recognized that the combination of different tapes within a singlecartridge 254 can also include other suitable types of tape that canvary depending upon the design requirements of the tape drive 246, suchas a cleaning tape as one non-exclusive example.

FIG. 3 is a side view of one embodiment of a portion of the tape drive346 including the tape head 360 and the controller 344, and a portion ofthe cartridge 354 including section of a tape 378. In this embodiment,the controller 344 controls movement of the tape head 360 in an up anddown oscillating manner, as indicated by arrow 386. More specifically,the controller 344 can control the frequency and/or amplitude ofoscillation of the tape head 360 relative to the tape 386. In analternative embodiment, the controller 344 can control movement of thetape head 360 in a direction that is different than strictly an up anddown movement. For example, in non-exclusive alternative embodiments,the controller 344 can control movement of the tape head 360 in adiagonal, lateral, circular or an elliptical motion.

The controller 344 can also control the lateral velocity, direction ofmovement (indicated by arrow 388), and/or duration of movement of thetape 378 across the tape head 360. In one embodiment, the controller 344can coordinate the frequency of oscillation of the tape head 360, thelateral velocity of the tape 378, the direction of movement of the tape378 and/or the duration of movement of the tape 378 in order to mitigateor correct one or more of the problems of the tape drive 346 identifiedherein.

The controller 344 can control the frequency of oscillation of the tapehead 360, the lateral velocity of the tape 378, the tension of the tape378 and/or duration of movement of the tape 378 across the tape head 360using one or more algorithms. In some embodiments, the algorithms can bebased on monitoring, improving and/or optimizing the results from one ormore of an output of the tape head, a resolution of a signal from thetape head, an error rate in reading of data by the tape head from thestorage tape, an error rate in writing of data by the tape head to thestorage tape, and a signal-to-noise ratio from the tape head, or anyother suitable parameter.

FIG. 4 is a side view of a portion of one embodiment of the tape 478 ofa combination cartridge 454C. In this embodiment, the tape 478 includesa magnetic storage tape 478D for storing data and a lapping tape 478Lfor lapping the tape head 360 (illustrated in FIG. 3). In oneembodiment, the storage tape 478D in the cartridge 454C is used fortesting purposes only, to determine the performance level of the tapehead 360 of the tape drive 346 (illustrated in FIG. 3). For example, ifthe controller 344 (illustrated in FIG. 3) detects a problem with thetape drive 346, the controller 344 can initiate a lapping operationduring which the lapping tape 478L is moved across the tape head 360 inan attempt to resolve the problem. Following the lapping operation, thetape head 360 can be tested by performing a read and/or write operationrelative to the storage tape 478D, without the need for removing thecartridge 454C that is presently in the tape drive 346. In analternative embodiment, the storage tape 478D can be used both fortesting the tape drive 346 as well as for actual storage of real databeing used by the user of the tape drive 346.

The proportion of the total length of the tape 478 that is storage tape478D versus lapping tape 478L can vary depending upon the designrequirements of the tape drive assembly 20 and/or the media library 10.In one embodiment, the tape 478 can be substantially equally dividedbetween storage tape 478D and lapping tape 478L. Alternatively, theratio of storage tape 478D to lapping tape 478L can be at leastapproximately 0.01, 0.1, 0.5, 0.75, 0.9, 1.1, 1.25, 1.5, 2.0, 5.0, 10.0or 100.0. Still alternatively, the ratio can be above or below theforegoing range.

The specific design of the lapping tape 478L can vary to suit the designrequirements of the tape drive assembly 20 and/or the media library 10.In one embodiment, the lapping tape 478L can include an abrasivematerial such as a 0.1 micron diamond material. In non-exclusivealternative embodiments, the lapping tape 478L can include a 0.5 micronor a 1.0 micron diamond material. Still alternatively, the size of thediamond material can be larger or smaller than these examples. Further,the abrasive material can be formed from another suitable element orcompound, provided the requisite level of lapping of the tape head 360can be achieved.

The length of the lapping tape 478 can likewise be varied. In oneembodiment, the length of the lapping tape 478 can be approximately 20feet. Alternatively, the length can be less than or greater than thislength.

The storage tape 478D and the lapping tape 478L can be spliced togetherin a similar manner that other types of magnetic recording tapes arespliced together, i.e. in a manner known to those skilled in the art.Further, the storage tape 478D and/or the lapping tape 478L can each beuninterruptedly positioned within the cartridge 454C, or the storagetape 478D and/or the lapping tape 478L can alternate, e.g., beintermittently or alternatingly positioned within the cartridge 454C.

The tension of the lapping tape 478L can be controlled by the controller344 (illustrated in FIG. 3) using an algorithm for adjusting the tensionof the tape 478, which can be based on one or more of the pliability ofthe tape 478, the curvature or other geometry of the tape head 360(illustrated in FIG. 3), and/or the grit of the lapping tape 478L, asnon-exclusive examples.

FIG. 5 is a side view of a portion of another embodiment of the tape 578of a combination cartridge 554C. In this embodiment, the tape 578includes a magnetic storage tape 578D for storing data, a first lappingtape 578L1 and a second lapping tape 578L2. In one embodiment, the firstlapping tape 578L1 can be substantially similar to the lapping tapepreviously described herein. The second lapping tape 578L2 can have adifferent grit than the first lapping tape 578L1. For example, thesecond lapping tape 578L2 can be more or less abrasive than the firstlapping tape 578L1. In addition, or in the alternative, the secondlapping tape 578L2 can include a different type of material, i.e. adifferent element or compound for lapping the tape head 360 (illustratedin FIG. 3) than the first lapping tape 578L1.

In the embodiment illustrated in FIG. 5, the first lapping tape 578L1and the second lapping tape 578L2 are positioned adjacent to oneanother. In an alternative embodiment, the first lapping tape 578L1 andthe second lapping tape 578L2 are separated by the storage tape 578D, orby another type of tape.

FIG. 6 is a side view of a portion of another embodiment of the tape 678of a combination cartridge 654C. In this embodiment, the tape 678includes a magnetic storage tape 678D for storing data, a lapping tape678L and a cleaning tape 678CL that is positioned between the storagetape 678D and the lapping tape 678L. Alternatively, the relativepositions of the tapes 678D, 678L, 678CL can be different than thatillustrated in FIG. 6. The cleaning tape 678CL can be a relativelynon-abrasive type of tape known to those skilled in the art, which canremove dust and or other loose particulates that can be present on thetape head 360 (illustrated in FIG. 3). The cleaning tape 678CL be formedfrom a material such as that used in Quantum Cleaning CartridgesTHXHC-02 DLT™, DLT-1 VS80™, and/or DLT VS160™, as various non-exclusiveexamples, although any suitable cleaning tape 678CL can be utilized inthe cartridge 654C.

FIG. 7 is a flow diagram illustrating one embodiment of a method forrepairing the tape drive in accordance with the present invention. Inthis embodiment, during normal operation of the tape drive, thecontroller determines whether read/write errors above a predeterminedthreshold level are occurring on a standard data cartridge (step 701).

It is recognized that although FIG. 7 refers to “read/write errors”,this can be mean either read errors or write errors, or a combination ofread and write errors. In addition or in the alternative, the controllercan equally monitor other types of errors or performance characteristicsof the tape drive to determine whether a predetermined threshold hasbeen surpassed (either too high or too low). No limitations on the typesof errors or performance characteristics of the tape drive that can bemonitored by the controller are intended by simply referring to“read/write errors” in FIG. 7. Further, the predetermined threshold canbe included as part of the firmware or drive circuitry of the tape driveand/or media library, or it can be manually input by an operator asrequired.

If the predetermined threshold is not exceeded, no corrective action isrequired (step 703). If the predetermined threshold of read/write errorsis exceeded, the controller can initiate insertion of a cleaningcartridge into the tape drive, and subsequent cleaning of the tape head(step 705).

Once cleaning of the tape head has concluded, the controller caninitiate reinsertion of the data cartridge (step 707). The controllerthen monitors the read/write errors to determine if they are still abovethe predetermined threshold (step 709). If not, no further correctiveaction is necessary (step 711). However, if the read/write errors aredetermined by the controller to exceed the predetermined threshold, thecontroller can take the tape drive off-line (such as in a media librarysetting) and can initiate insertion of a lapping cartridge and asubsequent lapping operation of the tape head (step 713).

Once the lapping operation has concluded, the controller can initiatereinsertion of the data cartridge into the tape drive (step 715). Thecontroller can then monitor read/write errors to determine whether theyexceed the predetermined threshold level (step 717). If not, no furthercorrective action is necessary (step 719). However, if the read/writeerrors exceed the predetermined threshold level, the controller candetermine based on changes of various parameters such as amplitude,resolution, signal-to-noise ration, etc., whether the tension of thelapping tape used in the most recent lapping operation must be increasedor reduced in order to achieve improved or optimum contact between thetape head and the storage tape (step 721). Alternatively, the controllermay determine that no adjustment of the tension is required. Thepredetermined optimum contact between the lapping tape and the tape headcan be achieved by following one of the known cursive methods ofadjustment and can be preset by the operator or it can be programmedinto the firmware of the tape drive.

The lapping process reduces the thickness of the sensor of the tape headby removing material from the sensing element. If the most recentlapping operation caused the sensor to reach a predetermined minimumthickness by monitoring the maximum allowable resistance or out of rangebias current level, the tape drive must be serviced more extensivelythan by the present invention (step 723), such as by the manufacturer oranother service technician, i.e. replacing the tape head at the factory.In one embodiment, the controller can alert the manufacturer, servicetechnician or another designated person to initiate the repair process.Further, the lapping service life is reduced with repeated usage of thelapping tape. If the predetermined maximum lifespan of the lapping tapeis reached during the most recent lapping operation as determined bylack of lapping effectiveness of removing material as measured by theparameters, the controller can insert a new lapping cartridge and repeatthe lapping operation. The normal steps of repair include modifying thetension of the lapping tape in incremental increasing or reducing stepsuntil the tape head performance is restored to an acceptable level (step725) as required by the design requirements of the tape drive, the tapedrive assembly or the media library.

Following the lapping operation at the required and/or optimum tension,the controller initiates reinsertion of the data cartridge (step 715),and the process repeats until the read/write errors no longer exceed thepredetermined threshold level (steps 717 and 719), or until the tapehead thickness has reached the predetermined minimum (steps 721 and723).

It is recognized that although FIG. 7 describes the “predeterminedmaximum” relative to lapping tension, this predetermined maximum canequally refer to frequency of oscillation of the tape head, lateralvelocity of the lapping tape across the tape head, or any combination oflapping tension, frequency of oscillation of the tape head and/orlateral velocity of the lapping tape across the tape head.

FIG. 8 is a flow diagram illustrating another embodiment of a method forrepairing the tape drive in accordance with the present invention. Inthis embodiment, during normal operation of the tape drive, thecontroller determines whether read/write errors above a predeterminedthreshold level are occurring on a standard data cartridge (step 827).

It is recognized that although FIG. 8 refers to “read/write errors”,this can be mean either read errors or write errors, or a combination ofread and write errors. In addition or in the alternative, the controllercan equally monitor other types of errors or performance characteristicsof the tape drive to determine whether a predetermined threshold hasbeen surpassed (either too high or too low). No limitations on the typesof errors or performance characteristics of the tape drive that can bemonitored by the controller are intended by simply referring to“read/write errors” in FIG. 8.

If the predetermined threshold is not exceeded, no corrective action isrequired (step 829). If the predetermined threshold of read/write errorsis exceeded, the controller can initiate insertion of a cleaningcartridge into the tape drive, and subsequent cleaning of the tape head(step 831).

Once cleaning of the tape head has concluded, the controller caninitiate reinsertion of the data cartridge (step 833). The controllerthen monitors the read/write errors to determine if they are still abovethe predetermined threshold (step 835). If not, no further correctiveaction is necessary (step 837). However, if the read/write errors aredetermined by the controller to exceed the predetermined threshold, thecontroller can take the tape drive off-line (such as in a media librarysetting) and can initiate insertion of a combination storage tape andlapping tape cartridge and a subsequent lapping operation of the tapehead (step 839).

Once the lapping operation has concluded, the controller can thenmonitor read/write errors relative to the storage tape of the samecartridge to determine whether they exceed the predetermined thresholdlevel (step 841). If not, no further corrective action is necessary andthe controller can place the tape drive back on-line for normaloperation (step 843). However, if the read/write errors exceed thepredetermined threshold level, the controller can determine whether thetension of the lapping tape used in the most recent lapping operationwas higher or lower than the optimum level (or some other acceptablelevel) by comparing the most recent lapping test results (step 845), andwhether the tension of the lapping tape should be adjusted.

If the MR resistance or bias current of the lapping tape in the mostrecent lapping operation has reached a predetermined maximum level, thetape drive must be serviced more extensively than by the presentinvention (step 847), such as by the manufacturer or another servicetechnician. In one embodiment, the controller can alert themanufacturer, service technician or another designated person toinitiate the repair process. If the predetermined MR resistance or biascurrent of the tape head had not yet been reached during the most recentlapping operation, e.g., the thickness of the sensor of the tape head isnot at or below a predetermined minimum thickness, the controller canrepeat the lapping operation with an adjusted tension of the lappingtape (step 849), i.e. higher or lower tension, as described previously.Alternatively, it may be determined that the tension does not need to beadjusted. In this embodiment, the lapping operation can be performedagain at substantially the same tension but for a longer duration, asone non-exclusive example.

Upon conclusion of the lapping operation (step 851), the controller canmonitor read/write errors relative to the storage tape of the samecartridge to determine whether they exceed the predetermined thresholdlevel (step 841). This process repeats until the read/write errors nolonger exceed the predetermined threshold level (steps 841 and 843), oruntil the tape head thickness has reached the predetermined minimum(steps 845 and 847).

Similar to the description of FIG. 7 above, it is recognized thatalthough FIG. 8 describes the “predetermined maximum” MR resistance orbias current, this predetermined maximum can equally refer to frequencyof oscillation of the tape head, lateral velocity of the lapping tapeacross the tape head, or any combination of lapping tension, frequencyof oscillation of the tape head and/or lateral velocity of the lappingtape across the tape head or the number of lapping operations aparticular tape head has undergone.

Furthermore, this remote repair operation can be applied to determinethe need and apply remote corrective non-intrusive traditional driverepair such as updating the micro code of the tape drive and any othersuitable tape drive settings prior to restoring the tape drive to anon-line status.

While the particular media library 10 and tape drive assemblies 20 asherein shown and disclosed in detail are fully capable of obtaining theobjects and providing the advantages herein before stated, it is to beunderstood that they are merely illustrative of the presently preferredembodiments of the invention and that no limitations are intended to thedetails of construction or design herein shown other than as describedin the appended claims.

1. A tape drive assembly for the transmission of data relative to amagnetic storage tape, the tape drive assembly comprising: a tape headthat magnetically interacts with the storage tape; a cartridge receiverthat selectively receives a cartridge having a lapping tape that lapsthe tape head; and a controller that dynamically adjusts one of (i) atension of the lapping tape relative to the tape head, (ii) anoscillation frequency of the tape head relative to the lapping tape, and(iii) a lateral velocity of the lapping tape relative to the tape head.2. The tape drive assembly of claim 1 wherein the cartridge includes thestorage tape and the lapping tape.
 3. The tape drive assembly of claim 1further comprising a drive housing that substantially contains the tapehead, the cartridge receiver and the controller.
 4. The tape driveassembly of claim 1 further comprising a drive housing thatsubstantially contains the tape head and the cartridge receiver, thecontroller being positioned remotely from the drive housing.
 5. The tapedrive assembly of claim 4 wherein the controller is part of a tapelibrary that includes the drive housing.
 6. The tape drive assembly ofclaim 1 wherein the controller uses an algorithm to adjust the tensionof the lapping tape relative to the tape head.
 7. The tape driveassembly of claim 6 wherein the algorithm is based on the pliability ofthe lapping tape.
 8. The tape drive assembly of claim 6 wherein thealgorithm is based on a curvature of the tape head.
 9. The tape driveassembly of claim 6 wherein the algorithm is based on the grit of thelapping tape.
 10. The tape drive assembly of claim 6 wherein thealgorithm is based on at least one of an output of the tape head, aresolution of a signal from the tape head, an error rate in reading ofdata by the tape head from the storage tape, an error rate in writing ofdata by the tape head to the storage tape, and a signal-to-noise ratiofrom the tape head.
 11. The tape drive assembly of claim 1 wherein thecontroller uses an algorithm to adjust the oscillation frequency of thetape head relative to the lapping tape.
 12. The tape drive assembly ofclaim 11 wherein the algorithm is based on the grit of the lapping tape.13. The tape drive assembly of claim 11 wherein the algorithm is basedon at least one of an output of the tape head, a resolution of a signalfrom the tape head, an error rate in reading of data by the tape headfrom the storage tape, an error rate in writing of data by the tape headto the storage tape, and a signal-to-noise ratio from the tape head. 14.The tape drive assembly of claim 1 wherein the oscillation of the tapehead is in a direction that is substantially perpendicular to thedirection of movement of the lapping tape.
 15. The tape drive assemblyof claim 1 wherein the controller uses an algorithm to adjust thelateral velocity of the lapping tape relative to the tape head.
 16. Thetape drive assembly of claim 15 wherein the algorithm is based on thegrit of the lapping tape.
 17. The tape drive assembly of claim 15wherein the algorithm is based on at least one of an output of the tapehead, a resolution of a signal from the tape head, an error rate inreading of data by the tape head from the storage tape, an error rate inwriting of data by the tape head to the storage tape, and asignal-to-noise ratio from the tape head.
 18. The tape drive assembly ofclaim 1 wherein the controller adjusts the duration of movement of thelapping tape over the tape head based on one of an output of the tapehead, a resolution of a signal from the head, an error rate in readingof data by the tape head from the storage tape, an error rate in writingof data by the tape head to the storage tape, and a signal-to-noiseratio from the tape head.
 19. The tape drive assembly of claim 1 whereinthe tape head and the cartridge receiver are included as part of a tapedrive, and wherein the controller takes the tape drive off-line based onat least one of an output of the tape head, a resolution of a signalfrom the tape head, an error rate in reading of data by the tape headfrom the storage tape, an error rate in writing of data by the tape headto the storage tape, and a signal-to-noise ratio from the tape head. 20.The tape drive assembly of claim 1 wherein the controller initiatesinsertion of the cartridge into the cartridge receiver to lap the tapehead with the lapping tape based on at least one of an output of thetape head, a resolution of a signal from the tape head, an error rate inreading of data by the tape head from the storage tape, an error rate inwriting of data by the tape head to the storage tape, and asignal-to-noise ratio from the tape head.
 21. The tape drive assembly ofclaim 1 wherein the controller dynamically adjusts each of the tensionof the lapping tape relative to the tape head, the oscillation frequencyof the head relative to the lapping tape and the lateral velocity of thelapping tape relative to the tape head.
 22. A media library includingthe tape drive assembly of claim 1 and a cartridge mover that moves thecartridge relative to the tape drive assembly.
 23. A tape drive assemblyfor the transmission of data relative to a magnetic storage tape, thetape drive assembly comprising: a tape head that magnetically interactswith the storage tape; a cartridge receiver that selectively receives acartridge having a lapping tape that laps the tape head; and acontroller that initiates insertion of the cartridge into the cartridgereceiver to lap the tape head based on one of an output of the tapehead, a resolution of a signal from the tape head, an error rate inreading of data by the tape head from the storage tape, an error rate inwriting of data by the tape head to the storage tape, and asignal-to-noise ratio from the tape head.
 24. The tape drive assembly ofclaim 23 wherein the controller dynamically adjusts one of (i) a tensionof the lapping tape relative to the tape head, (ii) an oscillationfrequency of the head relative to the lapping tape, (iii) a lateralvelocity of the lapping tape relative to the tape head, and (iv) aduration of movement of the lapping tape across the tape head.
 25. Thetape drive assembly of claim 24 wherein the controller uses an algorithmto adjust the tension of the lapping tape relative to the tape head. 26.The tape drive assembly of claim 25 wherein the algorithm is based onone of the pliability of the lapping tape, a curvature of the tape head,and the grit of the lapping tape.
 27. The tape drive assembly of claim25 wherein the algorithm is based on a number of separate occasions thetape head has been lapped by the lapping tape.
 28. The tape driveassembly of claim 24 wherein the controller uses an algorithm to adjustthe oscillation frequency of the tape head relative to the lapping tape.29. The tape drive assembly of claim 24 wherein the controller uses analgorithm to adjust the lateral velocity of the lapping tape relative tothe tape head.
 30. The tape drive assembly of claim 23 wherein thecartridge includes the storage tape and the lapping tape.
 31. The tapedrive assembly of claim 23 wherein the tape drive assembly is part of amedia library, and wherein the controller is adapted to take the tapedrive off-line prior to the controller initiating insertion of thecartridge into the cartridge receiver.
 32. The tape drive assembly ofclaim 23 wherein the controller dynamically adjusts each of the tensionof the lapping tape relative to the tape head, the oscillation frequencyof the head relative to the lapping tape and the lateral velocity of thelapping tape relative to the tape head.
 33. A media library includingthe tape drive assembly of claim 23 and a cartridge mover that moves thecartridge relative to the tape drive assembly.
 34. A method forrepairing a tape drive, the method comprising the step of: dynamicallyadjusting with a controller one of (i) a tension of a lapping tape thatmoves across a tape head of the tape drive, (ii) an oscillationfrequency of the tape head relative to the lapping tape, (iii) a lateralvelocity of the lapping tape relative to the tape head, and (iv) aduration of movement of the lapping tape across the tape head.
 35. Themethod of claim 34 further comprising the step of taking the tape driveoff-line using the controller prior to insertion of a cartridge thatincludes the lapping tape into a cartridge receiver of the tape drive.36. The method of claim 34 further comprising the step of initiatinginsertion of a cartridge having the lapping tape with the controllerbased upon one of an output of the tape head, a resolution of a signalfrom the tape head, an error rate in reading of data by the tape headfrom a storage tape, an error rate in writing of data by the tape headto the storage tape, and a signal-to-noise ratio from the tape head. 37.The method of claim 36 wherein the step of initiating insertion includesinserting a cartridge that includes both the lapping tape and a magneticstorage tape that stores data.
 38. A method for repairing a tape drive,the method comprising the step of: initiating insertion of a cartridgeinto a cartridge receiver of the tape drive with a controller to performa lapping operation of a tape head of the tape drive based on one of anoutput of the tape head, a resolution of a signal from the tape head, anerror rate in reading of data by the tape head from a storage tape, anerror rate in writing of data by the tape head to the storage tape, anda signal-to-noise ratio from the tape head.
 39. The method of claim 38further comprising the step of taking the tape drive off-line using thecontroller prior to insertion of the cartridge.
 40. The method of claim38 wherein the step of initiating insertion includes inserting acartridge that includes both the lapping tape and the storage tape.